1. Field of the Invention
The present invention relates to a computer system and, more particularly, to a computer system having a computer main body and an expansion unit capable of being freely attached/detached to/from the computer main body.
The present invention also relates to a computer system and, more particularly, to a computer system having a computer main body, a port replicator for relaying connection to an externally connected equipment, and an expansion unit loading an expansion equipment for expanding the function therein.
The present invention also relates to electronic equipment such as a computer system and, more particularly, to a controller, constituted as a one-chip controller by a semiconductor integrated circuit, for handling clock and digital signals, and electronic equipment using the one-chip controller.
The present invention also relates to a computer system such as a personal computer incorporating a CPU board and, more particularly, to a computer system having a cooling control mechanism for a CPU chip mounted in the CPU board or other heat generating components.
2. Description of the Related Art
In recent years, various personal computers of a laptop or notebook type, which can be easily carried and operated by a battery, have been developed. A portable computer of this type is constituted such that an expansion unit can be attached thereto as needed to expand the function.
The expansion unit has a plurality of expansion connectors. Various option cards can be attached to the connectors. Additionally, in order to suppress power consumption in a state without connection of the computer main body, in some expansion units, the voltage of a specific pin is monitored to detect connection of the expansion unit, and some expansion units can be powered on only when the computer main body is connected.
However, to use a mounted option card, the system configuration information of the portable computer must be rewritten for reconfiguration of the system. The system configuration information is normally rewritten at the time of starting the system on the basis of setup information or the like, which is set by the user. Conventionally, therefore, when the expansion unit is mounted in the computer main body in a power ON state, the computer main body cannot recognize the presence of the expansion unit, and the option card of the expansion unit cannot be used.
Recently, an operating system (OS) or BIOS (Basic Input/Output System) having a function of reconfiguring the system during starting the portable computer has been developed. By using an operating system or BIOS of this type, the system environment can be changed during starting the system into an environment allowing the use of the option card.
However, when the expansion unit is mounted in the computer main body in a power ON state, an unexpected current flows from the computer main body to the option card due to hot swap or the like. This may cause destruction of the option card of the expansion unit. Even if destruction of the option card is prevented, disadvantages such as hangup of the computer main body may be generated.
For this reason, actually, the expansion unit cannot be mounted during starting the system of the computer main body (in an ON state).
In addition, recent portable computers which are connected (docked) to expansion units are largely improved in performance. Furthermore, in recent years, a variety of optional equipments have been developed.
In these situations, various function expansion mechanisms are required for expansion units, and accordingly, the packaging density of components in a unit becomes higher making a unit housing bulky. In addition, a power supply unit in the expansion unit has a higher power and becomes heavy.
Therefore, when an expansion unit having a desired function is manufactured using the conventional manufacturing technique, the unit main body becomes bulky and heavy. A large space is needed to set the unit, resulting in difficulty in handling.
In the conventional expansion unit of this type, a power supply unit is incorporated in the unit to apply a power supply voltage to each section in the unit. For this reason, when the packaging density of components in the unit becomes higher, heat or noise generated from the power supply unit largely influences each component in the unit and poses a problem of reliability.
In the conventional expansion unit of this type, power supplies of the expansion unit and the personal computer mounted in the expansion unit are independently ON/OFF-controlled. Therefore, an erroneous operation may be caused by a shift of the power supply states.
In the conventional expansion unit of this type, the personal computer mounted in the expansion unit can be arbitrarily detached. For this reason, disadvantages such as data destruction by a detaching operation during the operation are likely to occur to degrade the security.
In the conventional expansion unit of this type, when an optional unit such is a hard disk unit is to be mounted, a tool such as a driver is used to partially disassemble the housing of the expansion unit, and the optical unit such as a hard disk unit is fixed at a predetermined position in the housing. Thereafter, the housing is assembled to store the optical unit in the expansion unit. Conventionally, storage or exchange of an optional unit is not facilitated, and much time and labor are needed.
In the conventional expansion unit of this type, when a personal computer is to be attached/detached, the power ON/OFF operation of the power supplies of the personal computer and the expansion unit must be independently performed in accordance with a predetermined feed/stop sequence, resulting in poor operability.
In the conventional expansion unit of this type, when the personal computer is mounted in the expansion unit, I/O ports of the personal computer, which include a printer connection port, a serial (RS-232C) port, and a CRT (R, G, and B) connection port, are closed. For this reason, the expansion unit also has the similar I/O ports, and a large number of connection interfaces must be conventionally provided to the unit housing. Therefore, as the unit becomes bulky, a large number of connector wiring lines are needed, resulting in complex structure of the expansion unit. In addition, in the above conventional structure, an expansion unit having I/O ports must be used even in a system configuration using no I/O port, which poses an economical problem.
As a controller constituted as a one-chip controller by a semiconductor integrated circuit for handling clock and digital signals, various controllers constituting a CPU chip or a family thereof are available. Such a one-chip controller for handling clock and digital signals greatly increases its processing speed in recent years. Along with this, an increase in power consumption, and accordingly, an increase in chip temperature pose serious problems.
As for a CPU chip, to solve the above problems, countermeasures including a reduction in power consumption by application of a CMOS, a reduction in voltages, and improvement of fins have been made. On the other hand, a clock speed for determining the processing speed of the CPU has increased from several MHz to several tens of MHz in recent years. Even with the above countermeasures, the power consumption and temperature of the chip greatly increase.
As for the mounting environment of the CPU chip, further size and weight reduction and a smaller setting space are required to the equipment main body of, e.g., a portable computer. Accordingly, the packaging density of electronic components per unit volume further increases.
When the CPU chip is mounted in such an environment, it is difficult to ensure a space for mounting fins. In addition, since many heat generating elements are mounted in the periphery, a mechanical heat dissipation effect cannot be expected. In this case, if an increase in temperature of the CPU chip is left as it is, the CPU itself erroneously operates to cause troubles such as hardware abnormality and circuit destruction, resulting in difficulty in restoration, as a matter of course.
Conventionally, a method is applied in which a temperature fuse or an element for measuring the temperature of the CPU chip is mounted at a position relatively close to the CPU chip, thereby switching the CPU clock in accordance with a temperature detected by the element.
In the conventional temperature control of this type, however, the internal temperature of the CPU chip cannot be directly measured. It must be indirectly measured through a package or a print board, so a change in temperature cannot be rapidly and accurately recognized. For this reason, conventionally, clock switching control must be performed in accordance with a set temperature having a large margin for safety. Therefore, the high-speed performance of the CPU cannot be sufficiently exhibited.
As described above, in the conventional one-chip controller for handling clock and digital signals of the CPU chip or the like, a change in temperature in the chip cannot be rapidly and accurately recognized, and clock switching control must be performed in accordance with a set temperature having a large margin for safety. Therefore, the performance of the CPU cannot be sufficiently exhibited.
In an electronic equipment such as a portable computer mounted with a CPU board, the processing performance (processing speed) is determined by the CPU clock frequency. More specifically, as the clock frequency is raised within a range of a defined threshold clock frequency of the CPU chip, the processing performance increases. However, with a higher processing speed, the power consumption increases in accordance with the clock frequency, and accordingly, the heat generation amount of the CPU chip also increases.
In a portable computer mounted with a CPU board of this type, to sufficiently exhibit the performance of the CPU chip, various types of chip cooling methods/mechanisms for dissipating heat generated in the CPU chip and suppressing an increase in temperature of the CPU chip are proposed and realized.
As a countermeasure for suppressing an increase in temperature of the CPU chip, a method is conventionally applied in which an ambient temperature in the periphery of the CPU chip is detected, and the clock frequency is controlled in accordance with the detection output. More specifically, when the ambient temperature in the periphery of the CPU chip amounts to a set temperature, the CPU clock frequency is lowered. Alternatively, the CPU clock frequency is controlled to be inversely proportional to the ambient temperature in the periphery of the CPU chip.
In the conventional temperature control, however, heat generated by the heat generating portion of the CPU chip is transferred in peripheral air, and the diffused ambient temperature is detected by a temperature sensor to control the clock frequency. With this structure, a relatively large time delay occurs until the heat of the CPU chip is reflected on the CPU clock frequency control. In addition, the accurate temperature of the heat generating portion cannot be detected. Since temperature control cannot be precisely and accurately performed, and a large margin must be ensured for an operating limitation temperature, the CPU chip cannot be operated at an almost threshold frequency. Therefore, conventionally, the performance of the CPU chip cannot be sufficiently used to realize high-speed processing by CPU clock at an almost threshold frequency.
When the temperature of the CPU chip amounts to a high temperature which does not allow continuation of a normal operation, the system operation must be stopped at that point of time. Otherwise, it may cause not only destruction of data which is being processed but also abnormality of hardware or software, resulting in difficultly in restoration.
When a portable computer is mounted in a function expansion unit for expanding the function of the portable computer, the heat dissipation port of the portable computer is closed by the function expansion unit, and the portable computer indirectly receives heat generated in the function expansion unit. For this reason, in a long-time use, the temperature in the housing of the portable computer may abnormally increase depending on the peripheral environment to accordingly cause destruction of data which is being processed or abnormality of hardware.
As described above, in the conventional CPU temperature control means, a relatively large time delay occurs until the temperature of the CPU chip is reflected on the CPU clock control, and highly precise temperature detection cannot be performed. For this reason, CPU chip temperature control cannot be precisely performed, and the performance of the CPU chip cannot be sufficiently used to realize a stable high-speed operation of the CPU chip at an almost threshold frequency.
When the temperature of the CPU chip amounts to a high temperature which does not allow continuation of a normal operation, the system operation must be stopped at that point of time. Otherwise, it may cause not only destruction of data which is being processed but also abnormality of hardware or software, resulting in difficultly in restoration. In addition, when a portable computer is mounted in a function expansion unit for expanding the function of the portable computer, the heat dissipation port of the portable computer is closed by the function expansion unit, and the portable computer indirectly receives heat generated in the function expansion unit. For this reason, in a long-time use, the temperature in the housing of the portable computer may abnormally increase depending on the peripheral environment to accordingly cause destruction of data which is being processed or abnormality of hardware.